Cadmoindite is an extremely rare sulfide mineral typically found as a volcanic sublimates. It is characterized by its metallic luster and dark appearance, usually identified through analytical testing rather than visual inspection by the casual collector.
Is this cadmoindite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch cadmoindite with a known reference. Cadmoindite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Cadmoindite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Cadmoindite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, dark gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: massive.
Often confused with
Cadmoindite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Cadmoindite leaves black, Sphalerite leaves white to yellow-brown; luster reads metallic on Cadmoindite and resinous to submetallic on Sphalerite.
How to tell apart: Streak differs — Cadmoindite leaves black, Galena leaves lead-gray.
Often found alongside cadmoindite
Minerals reported to co-occur with cadmoindite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CdIn₂S₄
- Mohs hardness
- 3-4
- Density
- 5.62 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Massive
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Volcanic Fumaroles
- Typical price
- $50-300 for micro-specimens
Where rockhounds find cadmoindite
Classic worldwide localities
- Tolbachik volcano, Russia
Field-hunting tip
Look in volcanic fumaroles country — that is the host setting where cadmoindite typically forms. If you start seeing cadmium sulfide, sulfur in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find cadmoindite on the map
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